Metabolic Monitoring, a Method and Apparatus for Indicating a Health-Related Condition of a Subject

1. An apparatus for indicating a health-related condition of a subject, wherein the health-related condition is a diabetes-related or glucose-related or insulin-related metabolic condition, comprising: an input interface for receiving a raw sequence of samples of a first biological quantity derived by a first measurement method, the first measurement method being an invasive measurement and having a first impact on the subject, and for receiving a raw sequence of samples of a second biological quantity derived by a second measurement method, the second being a non-invasive measurement and having a second impact on the subject, the biological quantities having a useful variation and a non-useful variation; wherein the first biological quantity gives a more accurate indication of the health-related condition of the subject than the second biological quantity, wherein the first biological quantity and the second biological quantity have a correlation to the health-related condition of the subject, and wherein the second impact is smaller than the first impact; a predictor for providing, for a certain time, for which no sample for the first biological quantity exists, an estimated value of the first biological quantity as a predicted sample using samples for the second biological quantity and, as far as available, samples for the first quantity; a filter for filtering a sequence having samples of the first biological quantity and at least one predicted sample, the filtered sequence having a useful variation and a reduced non-useful variation compared to the sequence before filtering, and an output interface for outputting at least an increase indication, a decrease indication or a remain unchanged indication as a trend of the data, the trend being representative to a useful variation of the health-related condition of the subject.

2. The apparatus in accordance with claim 1 , in which the first measurement method is a blood or plasma glucose measurement, and in which the second measurement method is a heart rate measurement, a blood pressure measurement or a method for obtaining a product of heart rate and blood pressure.

3. The apparatus in accordance with claim 1 , in which the input interface is arranged to receive, as the sequence of samples of the second biological quantity, a first sub-sequence of samples and a second sequence of samples, and wherein the apparatus further includes a combiner for combining the first sub-sequence of samples and the second subsequence of samples to obtain the sequence of samples of the second biological quantity, the combiner being arranged to perform a sample-wise multiplication.

4. The apparatus in accordance with claim 1 , in which the first biological quantity is a blood glucose level, a blood lipid level or a blood insulin level of the subject.

5. The apparatus in accordance with claim 1 , in which the first biological quantity is a blood glucose level.

6. The apparatus in accordance with claim 1 , in which the predictor is arranged to receive, as a training sequence, several samples derived by the first measurement method, and to receive, after the training phase, one or more samples derived by the second measurement method for a running period.

7. The apparatus in accordance with claim 6 , in which the running period extends until a time instant, at which a sample derived by the first measurement method is received as a predictor update value, or in which the running period is unlimited, so that the predictor is a free-running predictor after the training phase.

8. The apparatus in accordance with claim 1 , further comprising a data interpolator for providing an interpolated sample for a missing sample, at a time instant, of the biological quantity using one or more preceding samples or one or more subsequent samples to obtain the processed sequence having samples of the raw sequence and the interpolated sample.

9. The apparatus in accordance with claim 1 , in which the filter is a low-pass filter.

10. The apparatus in accordance with claim 9 , in which the low-pass filter has a cut-off frequency, which is set such that the low frequency energy for frequencies of a raw sequence or a processed sequence has a predetermined portion of a total energy of the raw sequence or the processed sequence.

11. The apparatus in accordance with claim 9 , further comprising a cut-off frequency calculator being arranged to determine the cut-off frequency using the following steps: determining different cut-off frequencies for a low-pass filter for filtering the samples to obtain filtered test signals; for each filtered test signal, deriving residual values based on the difference of the raw sequence and a filtered test signal to obtain a residual representation; based on the residual representation, determining a cut-off frequency individually adapted to the raw sequence of samples.

12. The apparatus in accordance with claim 11 , in which the cut-off frequency calculator is arranged to determine the cut-off frequency by: determining a first line using residual energies for low cut-off frequencies; determining a second line using residual energies for high cut-off frequencies; and finding an intersection point of the first line and the second line, the intersection point indicating the cut-off frequency.

13. The apparatus in accordance with claim 1 , in which the output interface is arranged to indicate the trend by an acoustic indicator, an optical indicator or a mechanical indicator, so that the decrease indication, the increase indication or the remain unchanged indication are acoustically, optically or mechanically different from each other.

14. The apparatus in accordance with claim 1 , in which the output interface is arranged to derive and output the trend from an actual value of the filtered sequence or an enhanced sequence, and a timely preceding value of the filtered sequence or the enhanced sequence.

15. The apparatus in accordance with claim 1 , in which the output interface is arranged to graphically display the filtered sequence or the enhanced sequence.

16. The apparatus in accordance with claim 1 , in which the output interface is arranged to graphically display a sequence of predicted values or a sequence of filtered predicted values, and, in addition, at least a further filtered or enhanced sequence.

17. The apparatus in accordance with claim 16 , in which the sequence of predicted values is a sequence of blood glucose values of the subject, and the additional biological parameter is a rate pressure product of the subject used for prediction of the blood glucose values.

18. The apparatus in accordance with claim 1 , in which the first measurement method is, in addition, an expensive or a biochemical measurement method or a measurement method based on a measuring of a liquid, and in which the second measurement method is, in addition, a less expensive or a physiological measurement method, or a method based on a non-liquid measurement.

19. The apparatus in accordance with claim 1 , in which the predictor is arranged to perform a regression algorithm, and in which the predictor is further arranged to receive an update value from the first measurement method after a running period, which includes at least three times an interval, at which samples for the second measurement method are received by the input interface.

20. A method of indicating a health-related condition of a subject, wherein the health-related condition is a diabetes-related or glucose-related or insulin-related metabolic condition, the method comprising: receiving a raw sequence of samples of a first biological quantity derived by a first measurement method, the first measurement method being an invasive measurement and having a first impact on the subject, the first biological quantity having a useful variation and a non-useful variation; receiving a raw sequence of samples of a second biological quantity derived by a second measurement method, the second measurement method being a non-invasive measurement and having a second impact on the subject, the second biological quantity having a useful variation and a non-useful variation; wherein the first biological quantity gives a more accurate indication of the health-related condition of the subject than the second biological quantity, wherein the first biological quantity and the second biological quantity have a correlation to the health-related condition of the subject, and wherein the second impact is smaller than the first impact; providing by prediction, for a certain time, for which no sample for the first biological quantity exists, an estimated value of the first biological quantity as a predicted sample using samples for the second biological quantity and, as far as available, samples for the first quantity; and using a processor, filtering a sequence having samples of the first biological quantity and at least one predicted sample, the filtered sequence having a useful variation and a reduced non-useful variation compared to the sequence before filtering; and outputting at least an increase indication, a decrease indication or a remain unchanged indication as a trend of the data, the trend being representative to a useful variation of the health-related condition of the subject.

21. A computer program embodied on a computer-readable medium having a program code which when executed causes a processor to perform a method of indicating a health-related condition of a subject, wherein the health-related condition is a diabetes-related or glucose-related or insulin-related metabolic condition, the method comprising: receiving a raw sequence of samples of a first biological quantity derived by a first measurement method, the first measurement method being an invasive measurement and having a first impact on the subject, the first biological quantity having a useful variation and a non-useful variation; receiving a raw sequence of samples of a second biological quantity derived by a second measurement method, the second measurement method being a non-invasive measurement and having a second impact on the subject, the second biological quantity having a useful variation and a non-useful variation; wherein the first biological quantity gives a more accurate indication of the health-related condition of the subject than the second biological quantity, wherein the first biological quantity and the second biological quantity have a correlation to the health-related condition of the subject, and wherein the second impact is smaller than the first impact; providing by prediction, for a certain time, for which no sample for the first biological quantity exists, an estimated value of the first biological quantity as a predicted sample using samples for the second biological quantity and, as far as available, samples for the first quantity; and filtering a sequence having samples of the first biological quantity and at least one predicted sample, the filtered sequence having a useful variation and a reduced non-useful variation compared to the sequence before filtering; and outputting at least an increase indication, a decrease indication or a remain unchanged indication as a trend of the data, the trend being representative to a useful variation of the health-related condition of the subject, when running on a computer.